1. Field of the Invention
The present invention generally involves the field of technology pertaining to gas burners. More specifically, the invention relates to an improved reignition device for use with gas burners, particularly sealed gas burners capable of a low turndown rate and having spark ignitors.
2. Description of the Prior Art
In general, range top burners are either of the open or sealed type. Range top burners which are open to secondary air for combustion typically have turndown rates to approximately 1,200-2,000 BTU/hr to maintain foods at a "warm" setting. In a sealed burner assembly, where the secondary air is drawn through a gap formed between the range top and the bottom of the pan or utensil resting on the grate above the burner head, a turndown rate of approximately 1,800-2,000 BTU/hr typically may be maintained.
For certain cooking operations, such as melting chocolate or preparing delicate sauces, it is desirable to turn down the input burner rate to approximately 900 BTU/hr. At these minimum input rates, the small flames about the burner face can be easily extinguished by various external influences such as slamming the oven door, setting a pot on the grates and drafts. Therefore, in order to operate a burner at such low input rates, a reignition feature must be provided.
It is hereto before been known in gas burner assemblies to provide a pilot flame, remote from the burner head, which remains ignited even when the gas to the burner head is turned off. In these known arrangements, when the gas applied to the burner head is turned on, the burner head flames are ignited by the pilot light flame. Since maintaining a constant pilot light is uneconomical burner arrangements with electronic ignition systems have been used instead. Such known systems operate to provide a spark either within the burner head or at the burner face in order to ignite the gas supplied to the burner. Although the spark ignition arrangements alleviate the need for a constantly burning pilot flame, they operate dependably only at the higher turndown rates discussed above.
One possible solution to this problem of providing a lower turndown rate while assuring reignition of the burner flames if extinguished would be to use an electronic flame monitoring system, in connection with a known spark ignition arrangement, which would sense the absence of a flame and cause a spark to be produced to reignite the burner. Unfortunately, this type of arrangement would involve costly electronic components. Therefore, there exists a need for a reignition device for a gas burner operating at low turndown rates which can economically and efficiently reignite the burner flames when these flames are extinguished by means other than the burner control system, i.e., an external influence.